Glare is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as strong or misaligned lighting or car headlamps at night. Glare is caused by a significant ratio of luminance between the task, that which is being looked at, for example a screen of a computational device, and the glare source for example the Sun. Factors such as the angle between the task and the glare source and eye adaptation have significant impacts on the experience of glare. Glare has been known to be a serious obstacle when using computational devices (e.g. smartphones) outdoors.
In modern times, however, people use computational devices, such as smartphones, at all times, indoors and outdoors. Therefore, in today's world, the use of a computational device outdoors is a day to day occurrence. Thus, the problem of using a computational device, and primarily viewing its display, in sunlight, is an everyday problem almost every person in western society is forced to deal with on a daily basis. The problem is especially acute when the interface of the device is a graphic user interface, such that it is necessary to view the device display in order to operate the device. Almost every person has encountered this difficulty, which, in extremely bright sunlight, becomes nearly impossible to overcome.
An eyepiece is a type of lens that is attached to a variety of optical devices such as microscopes. It is so named because it is usually the lens that is closest to the eye when someone looks through the device. The objective (the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image) lens or mirror collects light and brings it to focus creating an image. The eyepiece is placed near the focal point of the objective to magnify this image. The amount of magnification depends on the focal length (which is a measure of how strongly the system converges or diverges light) of the eyepiece.